Mechanism for winding photographic film

ABSTRACT

A mechanism for winding photographic film in a device such as a camera. The mechanism includes a rotary drive and a transmission for operating a film winder. The transmission includes a friction clutch which is capable of having the degree of friction thereof adjusted. The transmission coacts with the rotary drive for transmitting the drive therefrom to the film winder. In addition, the transmission responds automatically to an increasing load for automatically increasing the friction of the friction clutch, so that in this way the mechanism adapts itself to the size of the load and is capable of absorbing sudden load increases while maintaining a smooth film movement substantially free of any shocks.

Tlnitetil Mates Patent iEnornoto 3,042,333 7/1962Wilder..................................242/75.5

FORETGN PATENTS OR APPLICATIONS [54] MECHANTSM il fifi WilNilMNGWIlilUTTI GRAPHMZ lFlliLM 667,973 5/1949England................................242/75.5

[72] Inventor: Nohualti Enomoto, Okayashi, Japan PrimaryExaminer-Stanley N. Gilreath Assistant Examiner-Milt0n GersteinAttorney-Steinberg & Blake ABSTRACT [30] Foreign Application PriorityData Nov. 13,1968

43/822515 A mechanism for winding photographic film in a device such asa camera. The mechanism includes a rotary drive and a transmission foroperating a film winder. The transmission includes a friction clutchwhich is capable of having the degree of friction thereof adjusted. Thetransmission coacts with the rotary drive for transmitting the drivetherefrom to the film winder. in addition, the transmission respondsautomatically to an increasing load for automatically increasing thefriction of the friction clutch, so that in this way the mechanismadapts mmimemec Cmfl itself to the size of the load and is capable ofabsorbing sudden J load increases while maintaining a smooth filmmovement UNHTED STATES PATENTS substantially free of any shocks.

1,920,967 Carpenter................ ...242/205 5 lClnims, il Drawing,Figure PATENTEDFEB 22 I972 3, 3 ,5 g

INVENTOR NOBU/JKI ENG/V1070 MECHANISM FOR WINDWG li lilOTOGhAlPllilllCFILM BACKGROUND OlF THE INVENTION The present invention relates to thewinding of film.

As is well known, it is necessary in devices such as cameras and thelike to wind film, for example, after exposure thereof, onto a takcupspool or reel. The film is usually maintained in the film plane at thefilm gate by a pressure plate which is spring-pressed against the filmso that the film winding opera tions take place in opposition to thefriction at the pressure plate. In addition, the film is advanced in astepwise manner, frame by frame, as by a suitable claw mechanism, in thecase of a motion-picture camera, ,or example, and when the film tends tobe wound at a relatively high speed, as is the case when the diameter onthe takeup reel or spool reaches a substantial magnitude, there may be asudden application of tension in the film resulting in shock. The resultis a lack of smoothness in the film movement, so that a gradual startingand stopping of the film movement at the advance of each frame thereofcannot be maintained.

The above drawbacks are usually aggravated further by the fact thatconventional structures are designed to handle the greatest load whichis encountered. Thus, as the wound film builds on the takeup spool orreel, the weight of the latter increases requiring more power for thecontinued rotation of the takeup spool or reel, with the result that thepower available during the initial winding of the film is far too great.This factor also contributes to a jerky, nonsmooth film movement whichresults not only in undesirable stressing of the film but also inundesirable stressing of the mechanism.

SUMMARY OF THE INVENTION It is accordingly a primary object of theinvention to provide a structure which will avoid the above drawbacks.

In particular, it is an object of the invention to provide a structurecapable of reliably absorbing any sudden variation in load duringintermittent film transportation.

A further object of the invention is to provide a structure which willassure a smooth movement of film to a takeup spool or reel even though asudden tension and release of tension is encountered by the film.

Yet another object of the invention is to provide a structure which willoperate automatically to adapt the magnitude of the force which istransmitted to a film winder to the load which is encountered, so thatthe force transmitted to the film winder will increase gradually as theload increases.

Also, it is an object of the invention to provide a structure whichlends itself to an initial adjustment which is best for a givenmechanism.

The object of the present invention also includes the provision of astructure which is compact, simple and relatively inexpensive while atthe same time operating very reliably to achieve the desired results.

According to the invention, the mechanism includes a rotary drive meansand a transmission means for operating a film winder. The transmissionmeans includes a friction clutch provided with an adjusting means foradjusting the friction thereof. This transmission means coacts with therotary drive means for transmitting the drive therefrom to the filmwinder and for automatically actuating the adjusting means to increasethe friction of the friction clutch as the load at the film winderincreases.

BRIEF DESCRIPTION OF DRAWING The invention is illustrated by way ofexample in the accompanying drawing which forms part of this applicationand which shows in a schematic, perspective illustration one possibleembodiment of a structure according to the invention, with part of thestructure shown in phantom lines in the position assumed thereby uponencountering a load increase.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawing, arotary drive means 5 is illustrated therein. This rotary drive meanstakes the form of an elongated shaft supported at its ends for rotarymovement in any suitable stationary bearings. The illustrated structuremay form part of a photographic camera, for example, and stationarywalls of the camera may be provided with hearings to support the shaft dfor rotation about its axis.

In the illustrated example shaft 5 fixedly carries a gear I which mesheswith an idler gear 3 supported in any suitable way for rotation aboutits axis. This gear 3 in turn meshes with a pinion 2 fixed to the outputshaft of a motor I. such as a suitahle electric motor, so that in theillustrated example it is this motor l which forms a source of powerused for providing the rotary drive means 5 with its rotary movement.

The illustrated structure also includes. a transmission means foroperating a film winder 113. The film winder T3 is driven by the outputshaft I15 of the transmission means. In the illustrated example the filmwinder II? is in the form of a disk centrally fixed to the output shaftid to be rotated thereby and operatively connected in any suitable waywith a takeup reel or spool for rotating the latter to wind the filmthereon.

The transmission means further includes a gear I2 fixed to the shaft i5and a worm wheel It which meshes with the gear 112 and with a worm 9 ofthe transmission means. The transmission means also includes a frictionclutch h, 9 which is provided with an adjusting means for adjusting theforce of friction thereof.

This latter adjusting means is formed in part by the worm Q whichterminates at one end in the flange 9 which forms part of the frictionclutch by frictional engagement with the annular friction element dwhich surrounds the shaft 5. This adjusting means further includes acoil spring I which is coiled about the shaft d and presses at one endagainst the friction element 8 so as to urge the latter against thefriction element 9'. The opposite end of the coil spring 7 pressesagainst, or may be fixed with, a collar #6 which is releasably fixed ata selected location along the shaft 5 by a setscrew ti. At its endopposite from the end where the gear d is located, the shaft 5 fixedlycarries a collar Ml which engages the end of the worm i when the latteris in the solid-line position shown in the drawing. The worm 9 is formedwith an axial bore passing therethrough so that while it is supported bythe shaft. 5 it is freely rotatable and axially movable with respect tothe shaft 5. Therefore, the only rotary movement ot'the worm 9 whichwill result in rotation of the worm wheel llI must be derived from therotary drive means 5 through the friction clutch Ii, 9.

As a result of this construction, it is possible for the worm 9 to movein the direction of the arrow shown in the drawing to a position such asthe phantom line position where the spring 7 of the adjusting means iscompressed to a greater degree so as to increase the force of frictionat the friction clutch ti, 9'. A limiting means Ml is provided forlimiting the extent to which the worm 9 is axially movable along theshaft 5. This limiting means lid takes the form of a simple stationarystop member carried by any stationary component of the camera or thelike and situated in the path of movement of the worm 9, moreparticularly its end flange 9', so that in this way the extent to whichthe worm 9 can be axially displaced is limited.

The above structure operates as follows:

The structure described above and shown in the drawing may form part ofa motion-picture camera or a still camera. In the latter case theillustrated structure forms part of a still camera designed to makerapid exposures of film frames one after the other with the film beingtransported in this case by a known mechanism driven, for example, fromthe gear 45 in an unillustrated manner. In the case of a motion-picturecamera, a film-advancing claw mechanism, well known in the art, may alsobe driven through a suitable transmission which is unillustrated andwhich derives its motion from the gear d. In either case, when thecamera or the like is operated, the motor I is energized so as toactuate the rotary drive means formed by the shaft 5. Thus, at this timethe shaft 5 rotates continuously while the film is intermittentlytransported from one frame to the next. The exposed film is wound by thefilm winder 13 onto the unillustrated takeup reel or spool which isdriven from the film-winding disk 13 in any suitable manner. The driveis transmitted from the shaft 5 through the friction clutch 8, 9' to theworm 9 which rotates the worm wheel 11 so as to provide for rotation ofthe gear 12. The collar 6 is initially adjusted on the shaft 5, by wayof the setscrew 6, so as to provide for the spring 7 an initial degreeof compression, in accordance with the operating conditions. Thestructure will operate initially with a minimum force of friction at thefriction clutch 8, 9' but this force will be sufficient to initiate thewinding of the film at the beginning of the operations when the load isat a minimum. However, during the continued winding of the film the loadwill increase so that the worm wheel 11 will tend to remain stationarybecause the force of friction at the friction clutch is insufficient totransmit the required drive through the worm 9 to the worm wheel 11.Therefore, at this time the worm 9 will continue to rotate but will beincapable of continuing the rotation of the worm wheel 11. The result isthat the worm 9 instead moves axially with respect to the worm wheel 11in the direction of the arrow shown in the drawing, thus moving theentire friction clutch 8,9 together with the worm 9 axially along theshaft 5 toward the collar 6. In this way the distance between thefriction element 8 and the collar 6 is reduced so as to increase thecompression of the spring 7 and thus increase the friction of thefriction clutch. This adjustable movement will take place until theforce transmitted through the friction clutch is sufficiently great toaccommodate itself to the increased load, and then the wheel 11 willstart to turn so as to continue the film-winding operations. Thus, whenthe force of friction at the friction clutch exceeds the load whichtends to resist the rotation of the film winder 13, the rotation of thelatter will continue. When the load is reduced or eliminated, the worm 9will automatically return to its original position by expansion of thespring 7. The limiting means formed by the stop member 14 limits theextent to which the worm 9 can move toward the collar 6 so as to limitthe extent of compression of the spring 7. In this way the maximum forcewhich can be transmitted is determined. Thus, if it should happen, forexample, that for some unforeseen reason rotation of the film winder 13is rendered impossible and would result in injury to the components, theworm 9 will simply engage the limiting means 14 so that all that canhappen after this point is that the clutch will slip and the parts willnot become damaged. In this way forced rotation of the film winder 13 isprevented. As was indicated above the initial force of the spring 7 maybe adjusted by adjusting the position of the collar 6 along the shaft 5,and it will be noted that this adjustment not only determines theinitial compression of the spring 7 but also determines the maximumcompression thereof because adjusting of the collar 6 along the shaft 5also adjusts the position of the collar 6 with respect to the limitingmeans 14.

It is to be noted that when the diameter of the takeup reel or spoolbecomes fairly substantial, the increased diameter will result in morerapid linear movement of the film with a tendency toward excessiverotation of the film winder 13. However, such excessive rotation if itis encountered is absorbed by slippage at the friction clutch 8,9.Furthermore, due to rapid movement of the film and the intermittent filmtransportation, impacts are transmitted to the disk 13. However, theseimpacts are readily absorbed by movement of the worm 9 along the shaft 5and slippage at the clutch 8,9 so that such impacts are not transmitteddirectly to the drive system with the result that the components areprotected and will have a far greater operating life. It is to be noted,in particular, that the movement of the worm 9 along the shaft 5 withcompression and expansion of the spring 7 prevents any sudden tensionfrom being exerted upon the film which is wound onto the takeup reel orspool, so that there is a smooth starting and stoppin of the film in afully reliable manner at the film ate as each rame IS advanced to theexposure position. There ore,

when any sudden stopping of the rotation of the disk 13 is encounteredfor any reason, the reaction resulting from such a sudden termination ofthe rotary movement of the disk 13 will be reliably absorbed.

It is apparent, therefore, that the above-described structure of theinvention provides an exceedingly practical assembly which may be usedwith great advantage for purposes such as those set forth above.

What is claimed is:

1. In a mechanism for winding photographic film, rotary drive means andtransmission means for operating a film winder, said transmission meansincluding a friction clutch having an adjusting means for adjusting thefriction thereof, and said transmission means coacting with said rotarydrive means for transmitting the drive thereof to the film winder foroperating the latter and for automatically actuating said adjustingmeans to increase the friction of the friction clutch in response to anincreased load at the film winder, said rotary drive means being in theform of a rotary shaft and said transmission means including a wormformed with an axial bore through which said shaft freely extends sothat said worm is freely rotatable and axially movable with respect tosaid shaft, said transmission means including a worm wheel driven byrotation of said worm, and said friction clutch of said transmissionmeans directly transmitting rotary movement of said shaft to said wormand including a pair of friction clutch elements in permanent frictionalengagement with each other, one of said clutch elements being fixed tosaid worm, said worm wheel tending to remain stationary when the loadincreases so that the worm then rotates with respect to the worm wheelto be advanced axially along said shaft, and said adjusting means beingoperatively connected to the other of said clutch elements and saidshaft, for transmitting rotation of said shaft to said other clutchelement and for responding to the axial movement of said worm along saidshaft for increasing the friction of the friction clutch until the driveis again transmitted through the worm wheel, whereby the friction of theclutch is automatically increased to an extent which will again providefor rotation of the worm wheel by the worm.

2. The combination of claim 1 and wherein said adjusting means includesa coil spring coacting with said friction element and with said otherrotary drive shaft to transmit rotation of the latter through said otherfriction element to said worm, said worm when displaced along said driveshaft upon encountering an increasing load compressing said spring forincreasing the friction between the latter and the friction elementuntil the drive is again transmitted to said worm wheel.

3. The combination of claim 2 and wherein a collar is releasably fixedto said shaft and engages an end of said spring distant from saidfriction element, so that the location of said collar along said shaftcan be adjusted for determining initially the compression of saidspring.

4. The combination of claim 1 and wherein a stop means is situated inthe path of movement of said worm for limiting the extent of axialmovement thereof.

5. The combination of claim 1 and wherein a driving motor is operativelyconnected with said shaft for rotating the latter.

1. In a mechanism for winding photographic film, rotary drive means andtransmission means for operating a film winder, said transmission meansincluding a friction clutch having an adjusting means for adjusting thefriction thereof, and said transmission means coacting with said rotarydrive means for transmitting the drive thereof to the film winder foroperating the latter and for automatically actuating said adjustingmeans to increase the friction of the friction clutch in response to anincreased load at the film winder, said rotary drive means being in theform of a rotary shaft and said transmission means including a wormformed with an axial bore through which said shaft freely extends sothat said worm is freely rotatable and axially movable with respect tosaid shaft, said transmission means including a worm wheel driven byrotation of said worm, and said friction clutch of said transmissionmeans directly transmitting rotary movement of said shaft to said wormand including a pair of friction clutch elements in permanent frictionalengagement with each other, one of said clutch elements being fixed tosaid worm, said worm wheel tending to remain stationary when the loadincreases so that the worm then rotates with respect to the worm wheelto be advanced axially along said shaft, and said adjusting means beingoperatively connected to the other of said clutch elements and saidshaft, for transmitting rotation of said shaft to said other clutchelement and for responding to the axial movement of said worm along saidshaft for increasing the friction of the friction clutch until the driveis again transmitted through the worm wheel, whereby the friction of theclutch is automatically increased to an extent which will again providefor rotation of the worm wheel by the worm.
 2. The combination of claim1 and wherein said adjusting means includes a coil spring coacting withsaid friction element and with said other rotary drive shaft to transmitrotation of the latter through said other friction element to said worm,said worm when displaced along said drive shaft upon encountering anincreasing load compressing said spring for increasing the frictionbetween the latter and the friction element until the drive is againtransmitted to said worm wheel.
 3. The combination of claim 2 andwherein a collar is releasably fixed to said shaft and engages an end ofsaid spring distant from said friction element, so that the location ofsaid collar along said shaft can be adjusted for determining initiallythe compression of said spring.
 4. The combination of claim 1 andwherein a stop means is situated in the path of movement of said wormfor limiting the extent of axial movement thereof.
 5. The combination ofclaim 1 and wherein a driving motor is operatively connected with saidshaft for rotating the latter.